The Breast Pathology Core Resource provides the investigators of the SPORE with expert pathologic evaluation of breast lesions of patients entered into SPORE-related projects. Fresh tissue from surgical specimens are provided through the Tumor Procurement Services of the Department of Pathology. We obtain, select, catalogue, and store surgical specimens of breast tissue and cytological samples from patients treated at MSKCC for immunohistochemical, molecular genetic and other studies; characterize the gross and microscopic histopathology of breast specimens; maintain a database of information concerning standard prognostic variables; perform and interpret established immunohistochemical procedures; develop, implement and interpret new immunohistochemical procedures; develop, implement and interpret in situ hybridization procedures; microdissect thin paraffin embedded tissue sections of breast lesions to produce high selected. histologically documented samples for molecular analysis. Accomplishments include: The development of immunohistochemical techniques for the assessment of BCL2, BA, E-cadherin and p27; The evaluation of the laser microdissection instrument developed at the NIH; A series of immunohistochemical studies of the glucose transporters GLUTS 1-5 as markers of carcinoma versus hyperplasia in clinical specimens; A morphological and immunohistochemical analysis of pathologic features of tumors from BRCA 1/2 heterozygotes; The immunohistochemical study of HER2, p53, p27, BCL2, and BAX expression as markers of response to taxanes; An assessment of the expression of Rb and cyclin D1 in breast cancers treated with gossypol; Microdissections of DCIS to determine whether genotypic alterations are correlated with specific phenotypic patterns; Immunohistochemical and molecular studies of sentinel lymph nodes; Further studies of our database on a consecutive series of about 1000 patients treated for primary operable breast carcinoma at MSKCC.